使用express应用生成器生成express模板后，先写package.json

{
  "name": "mysql-test",
  "version": "0.0.1",
  "private": true,
  "scripts": {
    "start": "node ./bin/www"
  },
  "dependencies": {
    "body-parser": "~1.13.2",
    "cookie-parser": "~1.3.5",
    "debug": "~2.2.0",
    "ejs": "~2.3.3",
    "express": "~4.13.1",
    "morgan": "~1.6.1",
    "serve-favicon": "~2.3.0",
    "mysql":"*"
  }
}

npm install安装依赖

新建立两个文件夹，models和config

写一个config配置文件，去连接mysql的:

module.exports = {
    mysql_dev: {
        host: 'localhost',
        user: 'user',
        password: 'your password',
        database: 'your db name',
        connectionLimit: 10,
        supportBigNumbers: true
    }
};

再写上一个database.js文件：

var mysql = require('mysql');
var config = require('../config/config');

var pool = mysql.createPool(config.mysql_dev);

exports.pool = pool;

在models里建立一个User.js文件作为model：

    var db = require('./database');
    
    var User = function() {};
    
    User.prototype.find = function(id, callback) {
        var sql = "SELECT * FROM users WHERE id =?";
        // get a connection from the pool
        db.pool.getConnection(function(err, connection) {
            if (err) {
                callback(true);
                return;
            }
            // make the query
            connection.query(sql, [id], function(err, results) {
                if (err) {
                    callback(true);
                    return;
                }
                callback(false, results);
            });
        });
    };

module.exports = User;

最后在app.js里引入，再调用：

var User = require('./models/User');

//.......

app.get('/users/:userid',function(req,res){
    var userid = req.params.userid;
    var user = new User();
    user.find(userid,function(err,result){
        if(err){
            res.send('not found');
        }
        res.send(result.length === 1 ? result[0]:result);
    });

});

这样就简单地完成一个后端的node.js分级结构，前端提供rest请求。